Glass at a bus stop is shattered from an earlier shooting at a McDonald's in East Palo Alto, Calif. on Sunday, May 5 2013. The shooting resulted in six people having to go to the hospital.

Photo: James Tensuan, The Chronicle

Glass at a bus stop is shattered from an earlier shooting at a...

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A photographer takes images of a crime scene at a McDonald's in East Palo Alto, Calif. while investigating an earlier shooting on Sunday, May 5 2013. The shooting resulted in six people having to go to the hospital.

Photo: James Tensuan, The Chronicle

A photographer takes images of a crime scene at a McDonald's in...

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John Cook of the East Palo Alto Police Department addresses media in East Palo Alto, Calif. after a shooting on Sunday, May 5 2013. The shooting resulted in six people having to go to the hospital.

Photo: James Tensuan, The Chronicle

John Cook of the East Palo Alto Police Department addresses media...

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Markers are laid out at a crime scene at a McDonald's in East Palo Alto, Calif. while investigating an earlier shooting on Sunday, May 5 2013. The shooting resulted in six people having to go to the hospital.

Photo: James Tensuan, The Chronicle

Markers are laid out at a crime scene at a McDonald's in East Palo...

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Officers investigate broken glass at a bus stop in front of a McDonald's in East Palo Alto, Calif. while investigating an earlier shooting on Sunday, May 5 2013. The shooting resulted in six people having to go to the hospital.

A brazen daytime shooting in East Palo Alto on Sunday that injured a 6-year-old girl and her grandmother is the most recent indicator of an uptick in violent crime that authorities said they hope to quash.

That shooting, along with another Saturday night and a homicide eight days earlier, are likely indications that gang activity is ramping up, said East Palo Alto Police Chief Ron Davis.

Four young men with gang ties were shot Sunday at 2:45 p.m. while waiting at a bus stop outside a McDonald's on Bay Road near University Avenue, Davis said. A 6-year-old girl and her grandmother were also injured in the shooting - the grandmother was shot in the lower leg and the girl fell and cut herself on shattered glass as she tried to run away. All are expected to survive.

"It was a cowardly act and one this community will not tolerate," Davis said at a news conference Monday. "We won't let it be a trend."

The gang involved with the Sunday shooting is one that has been behind increased violence since January, Davis said, and he hopes to stop the violence by using suppression techniques that were used successfully with two other East Palo Alto gangs.

Officials said they have worked too hard to reduce violence in the past few years to have it rise again. Residents were often fearful of police or unwilling to testify, making it hard for police and prosecutors to gather enough evidence to arrest and convict someone - even when police officers knew who was behind most shootings and homicides.

"It took many years to rebuild the trust between East Palo Alto police and the community," said Mayor Ruben Abrica.

East Palo Alto has had four homicides so far in 2013 and had seven in 2012. In 2011, the city saw 40 gun assaults and twice as many in 2012.

The city's gang-fighting approach - which will be used to address this newer gang, Davis said - includes bringing together known gang leaders for "cease-fire" call-ins to encourage them to address their conflicts without resorting to shooting. The gang members are also offered social services to help them transition out of a gang lifestyle, including job training and substance abuse treatment options.

The city also is working with Andrew Papachristos, a Yale sociology professor, to help examine known gang members' social networks. He helps cities use pre-existing records of arrests, police contacts and service calls to pull together a web of gang members' associates and rivals. Identifying the most frequent perpetrators of violence, who are also most likely to be victims, can help direct law enforcement efforts.

"We believe in a very balanced approach" to stopping gang violence, Davis said. "We do want people to stop, we want to provide alternatives, we want to make our communities safe.

"But for those who reject the community's offers for assistance, for those who still try to traumatize and terrorize a community, so that a grandmother and a 6-year-old can't stand at a bus stop? Then the only thing I have for them is incarceration," Davis said.